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Lithium: Environmental Pollution and Health Effects
Lithium: Environmental Pollution and Health Effects H Aral and A Vecchio-Sadus, CSIRO Minerals, Clayton South, VIC, Australia & 2011 Elsevier B.V. All rights reserved.
Abbreviations FDA NIOSH
Food and Drug Administration National Institute for Occupational Safety and Health
It is used in nuclear fusion reactors where tritium is • produced from lithium for the deuterium–tritium fuel
• •
Glossary EC50 Concentration of a material in water, a single dose that is expected to cause a biological effect on 50% of a group of test animals LC50 Lethal concentration, the amount of a substance in air that, when given by inhalation over a specified period of time, is expected to cause the death in 50% of a defined animal population
• • •
Introduction Lithium is present in the earth’s crust at 0.002– 0.006 wt%. It is the 33rd most abundant element in nature and is distributed widely in trace amounts in rocks, soils, and surface, ground, and sea waters. Lithium is enriched in the continental crust over the mantle, especially in pegmatites and in some alkali granitoids where the content reaches a few percentage by weight. Weathering of rocks containing lithium-rich minerals releases lithium to the environment. As a result, lithium is found in varying amounts in all soils, primarily in the finer particle size fractions. Carbonates and calcareous shales precipitated from evaporated seawater or lagoon water can have higher lithium concentrations. Lithium has widespread use, which in turn affects the environment and the health of fauna and flora:
• • • • •
It is used as a flux to promote the fusing of metals during welding and soldering, as it prevents the formation of oxides during welding by absorbing impurities. It is used in glass and ceramics, including the glass for the 5.08 m telescope at Palomar Observatory in San Diego, California. It can be used to give red color to fireworks. Lithium metal is used as a reducing agent in illegal, amateur ‘methamphetamine labs.’ It is used as a catalyst in the production of synthetic rubber and plastics.
• • •
•
cycle. Lithium compounds are used in the medical treatment of bipolar disorder. Lithium stearate is a high-temperature lubricant grease used in military, industrial, automotive, aircraft, and marine applications. The lithium-based grease does not become hard when cooled, and it does not react with water or oxygen in the air. Lithium stearate is used as an additive in cosmetics and plastics. Lithium batteries are disposable (primary) batteries that have lithium metal or lithium compounds as an anode. Lithium-ion batteries are high-energy-density rechargeable batteries. Lithium–lead alloys are used to make tough ball bearings for machinery. Lithium–aluminum and lithium–magnesium alloys are very light but strong, and are used largely in making armored vehicles and in aerospace applications. Alloys of lithium with aluminum, cadmium, copper, and manganese are used in various aircraft parts. Lithium chloride and lithium bromide absorb moisture from air and are used as desiccants. Lithium niobate is used extensively in mobile phones and optical modulators as resonant crystals. Lithium niobate is also used to make optical glass. Lithium peroxide, lithium nitrate, lithium chlorate, and lithium perchlorate are used as oxidizing agents in rocket propellants and in providing oxygen to submarines and space capsules. Metallic lithium and LiAlH4 are also used as rocket propellants. Lithium peroxide (Li2O2) in the presence of moisture absorbs carbon dioxide to form lithium carbonate and release oxygen. Lithium hydroxide (LiOH) when heated with a fat produces lithium soap, which is used to thicken oils and is used commercially to manufacture lubricating greases. Lithium hydroxide absorbs carbon dioxide from the air by reacting with it to form lithium carbonate.
Details on various applications of major lithium products are shown in Table 1. Over the past decade, the production and the consumption of lithium have increased at an average of approximately 3% per annum. The increase in the production of lithium and its compounds is driven
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Table 1
Various applications of lithium and their indicative values
Application
Main compound
Glass/ceramics melting points Glass/ceramics glazing Aluminum Lubricants Batteries Pharmaceuticals Air-conditioning Synthetic rubber Other
Lithium Lithium carbonate Lithium carbonate Lithium hydroxide Lithium carbonate Butyllithium Lithium bromide Butyllithium Lithium carbonate
Volume (%)
Amount (thousand tons)
Estimated price (US$ kg1)
Estimated value (million US$)
8
5.8
2
11
13 6 17 12 5 11 5 18
9.4 4.3 12.2 8.6 3.6 7.9 3.6 13
2 2 4 12 15 6 15 3
18 8 48 101 53 46 53 38
Source: From Ebensperger A, Maxwell P, and Moscoso C (2005) The lithium industry: Its recent evolution and future prospects. Resources Policy 30: 218–231, with permission from Pergamon.
primarily by the battery industry. For example, there are millions of mobile phones, laptop computers, and cameras in use around the world that use lithium batteries (Figure 1). There is also an emerging use of lithium as a power storage device in electric and hybrid vehicles.
Sources of Lithium Lithium is found naturally in the aquatic and terrestrial environments, but in small concentrations (Table 2). Lithium is found primarily in ionic form in water. The lithium concentration in freshwater and seawater is on the microgram per liter level. Surface water contains lithium at levels between 1 and 10 mg l1, seawater contains approximately 0.18 mg l1 lithium, and the lithium concentrations in groundwater may reach 0.5 mg l1. Lithium in the aquatic environment in the United States has been detected at low concentrations (B0.002 mg l1) in the major rivers and at typically o0.04 mg l1 in surface waters, but could be higher in contaminated streams. Worldwide, mineral water contains 0.05–1.0 mg l1 lithium; however, higher levels up to 100 mg l1 can be found in some natural mineral waters. Some bottled mineral waters may contain 0.002–5.2 mg l1 dissolved lithium. The intake from drinking tap water has been reported to be from less than 0.001 to approximately 0.3 mg Li per day. However, very high intake via drinking water, more than 5 mg Li per day, has been reported in areas of northern Chile with lithium-rich soils. Intake from municipal drinking water in northern Chile could be up to 1.4 mg Li per day. Lithium could be leached to these waters from weathered lithium minerals in alkali granitic rocks and lithium-rich clays and soils. Rivers generally contain approximately 3 mg l1 Li, whereas in the lithium-rich soils of northern Chile, the lithium content of the surface waters could be as high as 6 mg l1. High concentrations of lithium may also occur
in waters sourcing from rocks that are inherently rich in lithium. The lithium concentration in major rivers varied from 0.67 mg l1 for the Amazon River to 0.87 mg l1 for the Congo, 4.0 mg l1 for the Ganges, and 5.6 mg l1 for the Mississippi River. The concentration of lithium in lakes could be higher due to evaporation. The concentration of lithium in major lakes is shown in Table 3. Lithium is found in natural brines (Salar de Atacama, Chile; Salar de Hombre Muerto; and Salar de Rincon, Argentina, in South America and Searle’s Lake and Clayton Valley in the USA) and lakes (Great Salt Lake, USA; Zabuye Lake, Tibet; Dachaidan, China; Dead Sea, Israel). The lithium content of these brines varies from 20 mg l1 in the Dead Sea to 1500 mg l1 in Salar de Atacama. Processing of brines and lithium-rich lakes may enhance the dispersion of lithium to a wider area and could cause environmental pollution. Thermal springs and volcanic fumaroles can contain higher levels of lithium than background levels. For example, in the sulfate-rich waters of the Mendelev volcano in Kuril Island (Russia), the lithium content reaches 927 mg l1. In the same springs, rubidium and barium concentrations are also high. In the Stolbovskie springs, Li content ranges between 264 and 398 mg l1. Lithium is enriched in the continental crust over the mantle, especially in pegmatites, the highly coarsegrained and relatively light-colored crystalline rocks composed mainly of minerals found in ordinary igneous rocks. In some alkali granitoids, the lithium content may reach up to several percentage by weight. Lithium tends to enter the mineral structure of pyroxenes and amphiboles, replacing Mg2þ and Fe2þ and later Al3þ sites, muscovites, and plagioclases. In the case of excess lithium in the magmatic melt, lithium forms its own minerals such as spodumene (LiAlSi2O6), petalite (LiAlSi4O10), amblygonite ((Li,Na)Al(F,OH)PO4), montebrasite (LiAl (PO4)(OH,F)), lithiophilite (LiMnPO4), and lepidolite (K(Li,Al)3(Si,Al)4O10(F,OH)2). Weathering of rocks containing these minerals releases lithium to the
Lithium: Environmental Pollution and Health Effects
Figure 1
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Various sizes and shapes of lithium batteries used in electronic equipment.
Table 2 Typical background concentrations of lithium in the environment Environment
Concentration
Freshwater (mg l1) Seawater (mg l1) Sediment (mg kg1) Soil (mg kg1) Earth’s crust (mg kg1) Atmosphere (ng m3)
0.07–40 0.17–0.19 56 3–350 20–60 2
Source: From Aral H and Vecchio-Sadus A (2008) Toxicity of lithium to humans and the environment - A literature review. Ecotoxicology and Environmental Safety 70: 349–356, with permission from Elsevier.
environment. Carbonates precipitated from evaporated lake water can have high lithium concentrations, as demonstrated by a Dead Sea aragonite with 19 ppm lithium. Calcareous shales from the Ellis Group of Yellowstone National Park have been shown to contain approximately 18 ppm lithium. Lithium is found in trace amounts in all soils, primarily in the clay fraction, and to a lesser extent in the organic soil fraction, in amounts ranging from 7 to
Table 3
Lithium concentrations of the world’s major lakes
Name
Li (mg l1)
Lake Tanganyika Caspian Sea Lake Baikal Dead Sea
0.014 0.280 2.0 14.0
200 mg g1. Sediments in sabkhas and evaporite deposits of lagoons may contain elevated levels of lithium along with boron, potassium, and magnesium salts. Authigenic clays (i.e., those occurring in the place where they were originally formed) are enriched in lithium (200–500 ppm in smectites) relative to other rock types (e.g., igneous rocks 30 ppm and detrital clays 70–80 ppm). Liþ has the weakest sorption chemistry of all the alkali metals, and its affinity with clays is considered to be due to the isomorphic substitution of Mg2þ for Al3þ in the octahedral layer, leaving a vacant position to accommodate Liþ. Lithium is selectively absorbed over other cations and apparently fixed in a non exchangeable form. Adsorption onto suspended sediments in rivers may also play a role, but preliminary experiments have suggested that only
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approximately 1 ppm lithium is adsorbed onto clays and riverbed sediments. Lithium concentrations are generally in proportion to magnesium concentrations due to ionic radius similarities, but are only poorly correlated with other major ions, for example, with silicon and potassium, even though lithium concentrations result almost exclusively from the weathering of aluminosilicates. This is consistent with the tendency of lithium to be retained in secondary clays, substituting for Mg2þ or occupying the vacancy generated by Mg2þ substitution of Al3þ. Lithium ore minerals are mined around the world in various places to make various lithium products. Mines are located in places such as Manona, Zaire; Bikita, Zimbabwe; Greenbushes, Western Australia; La Corne and Bernic Lakes, Canada; Kola Peninsula, Russia; and Altai Mountains, China. It has been reported that the total lithium reserve of the world is 29.8 million tons (Table 4), which is equal to approximately 1500 years’ supply at the current consumption rate of approximately 20 000 tons per annum. Spodumene and brine are processed to form a number of products for domestic and industrial use (see Figure 2).
Table 4
Lithium reserves of the world
Deposit
Li (million tons)
Pegmatites Continental brines Geothermal brines Oil field brines Hectorites Jadarite
7.60 17.59 1.00 0.75 2.00 0.85
Li2CO3 Glass Ceramics Aluminum C.C. Powder Batteries Glass Airconditioning Ceramics Chemicals Adhesives
Natural resources
Minerals (spodumene, etc.)
Brines
Lithium carbonate Li2CO3
Basics
Lithium Chemicals There are numerous lithium-based chemicals used in a variety of applications. Most of these chemicals dissolve in water in considerable amounts (Table 5). Lithium metal reacts slowly with water to form lithium hydroxide and hydrogen. Metallic lithium reacts with nitrogen gas at room temperature to form a black nitride. Lithium nitride in turn reacts with water to form ammonia and lithium hydroxide. Lithium metal can ignite spontaneously in damp air. Lithium reacts with ammonia to form the amide, which on heating yields ammonia and lithium imide (Li2NH). At 500–700 1C, lithium reacts with hydrogen to form lithium hydride. Lithium hydride is an odorless, off-white to gray crystalline solid or a white powder. Airborne dust clouds of lithium hydride may explode on contact with heat. In the presence of moisture, lithium hexafluoroarsenate has the potential to form hydrogen fluoride, a highly corrosive gas. Lithium metal is flammable and potentially explosive when suddenly exposed to air and especially to water. The lithium–water reaction at normal temperatures is vigorous. Lithium fires are difficult to extinguish and require special chemicals designed to smother them. Metallic lithium is classified as a health, physiochemical, or ecotoxicological hazard. Lithium compounds such as lithium aluminum hydride and lithium methanolate are classified as dangerous goods. Lithium salts are not very toxic, except for the highly corrosive and irritant lithium hydrides, lithium tetrahydroaluminate (LiAlH4), and lithium tetrahydroborate (LiBH4). Spodumene, the major lithium ore mined in various places around the world, is an aluminum silicate.
Performance Secondary batteries Pharmaceutical Several
Specialty inorganics Greases
Bar/sheet
Lithium hydroxide LiOH Lithium chloride LiCl
Metal lithium
Primary batteries Aleacionesdealuminio Secondary batteries
Butyl lithium
Polymers Pharmaceutical
Specialty inorganics
Polymers Pharmaceutical
Pharmaceutical Gases separation Dehumidification Fluxesundentes
Figure 2 Processing of spodumene and brine sources to value-added products. C.C. Powder, ceramic coating powder. From Ebensperger A, Maxwell P, and Moscoso C (2005) The lithium industry: Its recent evolution and future prospects. Resources Policy 30: 218–231, with permission from Pergamon. .
Lithium: Environmental Pollution and Health Effects Table 5
Water solubility of some lithium compounds
Substance
Solubility in water
Lithium Lithium hydride Lithium acetate Lithium oxide Lithium hydroxide Lithium hydroxide monohydrate Lithium carbonate Lithium bromide Lithium chloride Lithium fluoride Lithium nitrate Lithium stearate
Decomposes to LiOH and H2 Decomposes to LiOH and H2 3000 g l1 (15 1C) 66.7 g l1 (0 1C); 100.2 g l1 (100 1C) 128 g l1 (20 1C); 175 g l1 (100 1C) 223 g l1 (10 1C); 268 g l1 (80 1C) 15.4 g l1 (0 1C); 7.2 g l1 (100 1C) 1450 g l1 (4 1C); 2540 g l1 (90 1C) 637 g l1 (0 1C); 1300 g l1 (96 1C) 2.7 g l1 (18 1C) 898 g l1 (28 1C); 2340 g l1 (100 1C) 0.1 g l1 (18 1C)
Source: Weast RC (1987) Handbook of Chemistry and Physics, 68th edn. Boca Raton, FL: CRC Press. 1987.
Table 6 Solubility (24 h, 40 1C) of various lithium minerals in water and various concentrations of sulfuric acid Sample lithium mineral concentrate
Aqueous reagent
Dissolved Li (mg l 1)
Spodumene
Distilled H2O 0.01 M H2SO4 0.1 M H2SO4 1.0 M H2SO4 Distilled H2O 2.5 M H2SO4 Distilled H2O 2.5 M H2SO4 0.01 M H2SO4 2.5 M H2SO4 0.01 M H2SO4
1.5 5.8 8.8 12.0 41.0 975 13.6 358 80.0 633 1.9
Amblygonite Lepidolite Lithiophilite Petalite
It contains up to 8.0 wt% Li2O, and this lithium is tightly bound to the crystal structure, and therefore, it alone does not pose a toxicological problem. However, when spodumene is crushed, it generates silica-rich dust, which is a health hazard. Finely ground lithium minerals, especially lithium-containing phosphate ores, are more susceptible to water and dilute acid leaching than unground ores due to increased surface area (Table 6).
Sources and Routes of Lithium Exposure People can be exposed to lithium through occupational, environmental, consumer, and medical sources. Occupational exposure to lithium occurs during the extraction of crude oil and natural gas, mining and processing of lithium minerals, and battery production. Environmental sources of exposure to lithium are primarily from soil and water. Consumer exposure could potentially occur from the use of products containing lithium (e.g., batteries and grease) and from mineral supplements.
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Medical exposure to lithium occurs through therapeutic applications. Occupational exposures to lithium may occur during extraction of lithium from ores, preparation of lithium compounds, welding, and enameling. In industrial environments such as mines and processing plants, workers and maintenance personnel may come in direct contact with lithium-containing dust. A NIOSH (National Institute for Occupational Safety and Health) study identified that workers in a lithium-processing plant experienced an estimated daily dose of 0.000 16–0.82 mg Li per kg of bodyweight. During welding, lithium vapors may be emitted from lithium-containing fluxes. The red color of firecrackers is mostly produced from the use of metallic lithium. Considerable amounts of lithium are discharged to the environment during New Year celebrations. The inhalation of lithium compounds and the ingestion of inhaled particles are most likely to take place through occupational exposures. The food humans consume, the water they drink, and the air they breathe may contain more than average levels of lithium, depending on the location. Occupational and natural lithium emissions may result in lithium concentrations in water and soils. Exposure routes to humans may include inhalation of dust, ingestion of contaminated water, or ingestion of foods grown in contaminated soils. There is negligible inhalation of lithium from air as ambient air levels are low (2–4 ng m3). In places where lithium brines crystallize by evaporation, the lithium content of the air could be higher. There is negligible absorption of lithium through the skin. Lithium may be found in some plants and animals in higher concentrations than the average, depending on the geographical location. A number of studies from different countries have reported intake levels from food ranging from 0.02 to 0.54 mg Li per day. An American assessment found that the average daily lithium intake of a 70 kg adult (American) is between 0.65 and 3.1 mg per day. Major dietary sources of lithium are grains and vegetables (0.5–3.4 mg Li per kg food), dairy products (0.50 mg Li per kg food), and meat (0.012 mg Li per kg food). In places like Chile where lithium-rich salinas could contain up to 1500 mg l1 Li, the total lithium intake may reach 10 mg kg1 without evidence of adverse effects to the local population. A review of the dietary intake of lithium has indicated that the minimum human adult (physiological) lithium requirement is estimated to be less than 0.1 mg per day. Based on lithium intake data in different countries, a provisional recommended daily intake of 1.0 mg Li per day for a 70 kg adult American was proposed, corresponding to 14.3 mg kg1 bodyweight, which can be derived by diet alone. People on special diets or populations residing in naturally low-lithium areas would require lithium supplements or other appropriate measures to meet this intake. Lithium levels in
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humans may be higher after physical exertion, in certain diseases and in dialysis patients. The highest exposure to lithium generally results from oral intake in therapeutic doses, although total lithium exposure and body burden is also geographically variable. Reported Li levels in serum of healthy subjects generally range from 1.1 to 59.7 mg l1, but levels up to 83 mg l1 have been reported, with the highest levels found in Chile. The typical plasma Li concentration is 14–21 mg l1. After oral administration of immediate-release lithium tablets, the maximal plasma concentrations are 1000-fold greater than typical trace concentrations. Consumption of mineral supplements could result in an additional internal dose of 5–6 mg Li per day.
Toxicity and Health Effects of Lithium Exposure Lithium does not have a known biological use and does not appear to be an essential element for human life. The amount of lithium in the human body is approximately 7 mg. Lithium is absorbed from the gastrointestinal tract and excreted primarily through the kidneys after approximately 24 h. Serum concentrations of lithium reach a peak approximately 30 min after oral ingestion, followed by a plateau at 12–24 h. Lithium ions cross the cell membrane slowly; this may account not only for the prolonged excretion of lithium but also for the delay of 6–10 days needed to achieve the full therapeutic response in humans. Although lithium is not an essential element, it may influence metabolism. A great deal of knowledge surrounding the toxicity of lithium has emerged from its extensive use in the medical industry. Lithium was first introduced into the medical profession in the mid-1800s as a cure-all for many common illnesses. The therapeutic levels of lithium are clearly able to inhibit functioning of multiple enzymes in the body. Lithium, as a medicine, has multiple effects on embryonic development, glycogen synthesis, hematopoiesis (the formation and development of blood cells involving both proliferation and differentiation from stem cells), and other processes. Common side effects of lithium treatment include muscle tremors, twitching, ataxia, bone loss, kidney damage, nephrogenic diabetes insipidus (polyuria and polydipsia), and seizures. Many of the side effects are the result of increased elimination of potassium. In 1949, lithium was banned from use in the United States because of excessive toxicity and did not gain FDA (Food and Drug Administration) approval for use in the treatment of mania until 1970. For more than 50 years, lithium has been the drug of choice for the treatment of recurrent bipolar disorder and has gained popularity as a pharmacologic option in the treatment of other psychiatric conditions because the
primary target organ for lithium is the central nervous system. Lithium salts, especially lithium carbonate and lithium acetate, are used extensively in the treatment of manic-depressive disorders. In the medical use of lithium salts, lithium ion Liþ, which has a smaller diameter, displaces Kþ and Naþ and in some cases Ca2þ, Mg2þ, and Zn2þ, in various enzymes. The therapeutic window between effective lithium dose and lithium toxicity is narrow. The therapeutic serum concentrations are normally approximately 5.6–8.4 mg l1, mild toxicity is usually seen at approximately 10.5–17.5 mg l1, moderate toxicity is seen at approximately 17.5–24.5 mg lF1, and severe symptoms are seen at 424.5 mg l1. Side effects are common even within the therapeutic dose range, and a significant number of patients do not respond. In one example, the vast majority (75–90%) of patients receiving maintenance lithium therapy for bipolar disorder became toxic at some point during their course of therapy. In 1996, 5102 lithium exposures were reported to the American Association of Poison Control Centers, with nearly 75% of those suffering exposure seeking medical attention.
Epidemiology Epidemiological studies have not clearly established a relationship between naturally occurring lithium and its positive or negative effects on humans. Limited information on possible carcinogenic and genetic effects of lithium compounds has been published to date. Most of the existing epidemiological studies were performed on laboratory animals. Study of incidents relating to human gender, race, and social status is rare.
Teratogenicity Teratogenicity is the ability to cause defects in a developing fetus. It is a potential side effect of many drugs such as thalidomide. Many authors have reported that lithium causes congenital defects, especially of the cardiovascular system such as Ebstein’s anomaly (a rare cardiac defect), when given to women during the first trimester of pregnancy. This claim gave rise to the foundation of a ‘Register of Lithium Babies’ in Risskov (Denmark) and later of an ‘American Registry of Lithium Babies’ in San Francisco. A first analysis (published in 1971) of the records of 60 children born by mothers who received lithium treatment during the first trimester or the entire pregnancy did not reveal any association of lithium treatment with a higher teratogenic risk. A multicenter study of pregnancy outcome after therapeutic lithium exposure during the first trimester also did not show any significant teratogenic risk.
Lithium: Environmental Pollution and Health Effects
Mutagenicity Mutagenicity is the ability to cause genetic mutations in sperms, eggs, and other cells. Despite the extensive therapeutic use of lithium carbonate, few investigations on the mutagenic potential of lithium compounds have been carried out. Lithium could have several ways of acting on DNA: Liþ binds selectively to DNA; it competes with Mg2þ and may impair DNA synthesis and DNA repair. Lithium carbonate added at the start of a 72 h culture period at concentrations equivalent to 0.1, 1.0, or 10 g of lithium carbonate distributed in the body of a 70 kg person did not increase structural chromosome aberrations in peripheral lymphocytes. No aberrations were found in 19 lithium-treated manic-depressive patients compared with 23 controls, but the mitotic index was significantly reduced. Similarly, no aberrations were observed in peripheral lymphocytes of as many as 77 patients studied, 50 of whom had been treated with lithium sulfate, 17 with lithium carbonate, and 10 with lithium acetate. Also, 16 manic-depressive patients who had been given lithium carbonate from 2 weeks to more than 2 years (seven of them for more than a year) did not show aberrations in their lymphocytes.
Environmental Pollution and Toxicology Geochemically, lithium is a highly mobile element; hence, lithium in aquatic environments can be transported long distances from the source. There are potential environmental impacts from the increased mining and use of lithium and its compounds. Increased levels of lithium in aquatic and terrestrial environments would affect the food chain. High lithium levels in soil may be phytotoxic and reduce biomass in crops.
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(Ptychocheilus lucius), razorback sucker (Xyrauchen texanus), and bonytail (Gila elegans) in the water simulating the middle Green River. This study showed that the overall rank order of toxicity to all species and life stages combined from most to least toxic was vanadium ¼ zinc 4 selenite 4 lithium ¼ uranium 4 selenate 4 boron. Studies have identified lithium toxicity levels in certain organisms (Table 7). Effective concentration (EC50) is the concentration of a material in water, a single dose that is expected to cause a biological effect on 50% of a group of test animals. Lethal concentration (LC50) is the amount of a substance in air that, when given by inhalation over a specified period of time, is expected to cause the death in 50% of a defined animal population. The presence of sodium is sufficient to prevent lithium toxicity to Pimephales promelas (fathead minnow), Ceriodaphnia dubia, and Elimia clavaeformis (a freshwater snail) in most natural waters. The acute environmental effect concentration (measured as EC50) on Daphnia magna was determined to be 33–197 mg l1, which is at least 1000 times higher than the level in freshwater. Both lithium chloride and lithium sulfate have high water solubility, and the compounds will dissociate in aqueous environment. No lithium compounds are classified for adverse environmental effects. No data regarding bioaccumulation of lithium were found, but based on its low affinity to particles, it is not expected to bioaccumulate. In Salar de Uyuni in Bolivia, lithium is dispersed over a 9000 km2 salt flat at 3600 m altitude in the Andes. Salar de Uyuni is classified by the tourist industry as a land of outstanding natural beauty. The area becomes a flamingo breeding ground from December to February when the rain floods the surface of the salar between January and March. The discharge of the Rio Grande into the salar, adjacent to where the lithium concentration is highest, creates a permanent lagoon area used by the birds.
Aquatic Environment Investigations were carried out on the acute toxicity of boron, lithium, selenate, selenite, uranium, vanadium, and zinc to early stages of development of Colorado squaw fish
Table 7
Terrestrial Environment Lithium is taken up by all plants, although it is not an essential nutrient for their growth and development. In
Test results for environmental (aquatic) toxicity
Species
Latin name (common name)
Compound
Exposure duration
EC50 (mg l1)
Mollusc
Dreissena polymorpha (zebra mussel) Daphnia magna (water flea) Tubifex tubifex (tubicid worm) Pimephales promelas (fathead minnow) Tanichthys albonubes (white cloud mountain minnow)
LiCl
24 h
–
Li2SO4 Li2SO4 LiCl
24 h 24–96 h 26 days
LiCl
48 h
Crustacean Worm Fish
33–197 9.3–44.8 1–6.4 –
LC50 (mg l1) 185–232 – – 1.2–8.7 9.2–62
Source: From Aral H and Vecchio-Sadus A (2008) Toxicity of lithium to humans and the environment – A literature review. Ecotoxicology and Environmental Safety 70: 349–356, with permission from Elsevier.
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some cases, stimulation of plant growth has been observed. Lithium is relatively toxic to citrus plants. The amount of lithium in plants usually lies between 0.2 and 30 ppm due to preferential uptake or rejection across species. Plants such as Cirsium arvense and Solanum dulcamera accumulate lithium in concentrations of three- to sixfold over other plants. Nightshade species may reach concentrations of up to 1 mg g1. Salt-tolerant plants such as Carduus arvense and Holoschoenus vulgaris may reach lithium contents of 99.6–226.4 mg g1. Lithium concentrations vary widely from 0.01 ppm (dry basis) in bananas to 55 ppm in oats. There appears to be a greater uptake of lithium by plants in acidic soils. Soil acidity increases the solubility of the heavier metallic elements such as iron, nickel, cobalt, manganese, and copper, and to some extent also aluminum, lead, and cadmium. Plant lithium levels are directly and significantly correlated with the concentrations of these elements. Calcium can be added to soils to prevent toxicity and the uptake of lighter minerals. Lithium in plants and animals interacts with sodium and potassium as well as with enzymes requiring magnesium. Its complexing properties are stronger than those of Naþ and Kþ but weaker than those of Mg2þ. At concentrations attained during therapy, Liþ and Mg2þ are present in comparable concentrations; thus, Liþ binds to sites not occupied by Mg2þ. Once all Mg2þ sites are saturated, Liþ substitutes for Naþ and Kþ. All alkali metal ions are exchanged more than 1000 times more rapidly than Mg2þ; this may explain why lithium preferentially affects the activity of Mg2þ-containing enzymes. Chlorophyll mutants were produced in the progeny of Pisum abyssinicum plants treated with lithium nitrate in addition to other nitrates (Cu, Zn, Cr, Mn, Fe, Co, Ni, and Al). This was most likely due to the presence of the other confirmed mutagenic metal nitrates. Yeast (Saccharomyces cerevisiae) has been shown to take up limited amounts of lithium, with growth inhibition exhibited at high levels (115–400 ppm). A high ability to accumulate lithium was exhibited by strains of the bacteria Arthrobacter nicotianae (B1.0 mg g1 dry weight cells) and Brevibacterium helvovolum (B0.7 mg g1 dry weight cells). Exposure of earthworms (Eisenia fetida) to lithium chloride identified a mortality rate at concentrations of approximately B70 mg kg1 soil. A limited investigation of the levels of lithium and other elements in major emissions and waste streams was conducted in Denmark in 2001. In the Danish study, lithium was found in all environmental samples especially compost, wastewater, sewage sludge, and sediment from road runoff retention basins (Table 8). The concentration in effluent from wastewater treatment plants was low and was not considered as being acutely toxic to aquatic organisms.
Table 8 Levels of lithium in selected emissions and waste products in Denmark Emission/waste type
Li concentration
Compost: Compost from household waste 4.64 mg kg1 Compost from garden waste 4.69 mg kg1 Landfill leachate: Landfill 1 0.2 mg l1 Landfill 2 0.049 mg l1 Stack gas from municipal solid waste incineration: Incinerator 1, semidry gas cleaning o9.1 mg m3 Incinerator 2, wet gas cleaning 1.0 mg m3 Municipal solid waste gas cleaning residuals: Landfill leachate, semidry gas cleaning 0.285 mg l1 Landfill leachate, wet gas cleaning 0.367 mg l1 Wastewater and sludge from municipal wastewater treatment plant: Plant 1, effluent 11.4 mg l1 Plant 2, effluent 21.2 mg l1 Plant 1, sludge 6.06 mg kg1 Plant 2, sludge 5.02 mg kg1 Road runoff retention basins, sediment: Motorway 1 16.3 mg kg1 Motorway 2 15.5 mg kg1 Source: From Aral H and Vecchio-Sadus A (2008) Toxicity of lithium to humans and the environment – A literature review. Ecotoxicology and Environmental Safety 70: 349–356, with permission from Elsevier.
Mining-Related Pollution Mining and mineral-processing industries producing lithium minerals, metals, and salts contribute to the lithium burden in the environment. The processing of lithium-containing minerals such as spodumene, in general, comprises crushing, wet grinding in a ball mill, sizing, gravity concentration, and flotation using a fatty acid (oleic acid) as the collector. The major lithium mineral in lithium ore is spodumene, which is considered insoluble in water and dilute acids. However, a small amount of dissolution may occur during processing of the ore especially in the grinding and flotation stages where some dilute (0.01 M) sulfuric acid is used (see Table 6). Tailings are discharged to storage areas, and the decanted water is usually recovered for reuse. Lithium concentrations in tailing dams increase gradually. The dissolved lithium found in the tailing dams of lithium mineral beneficiation plants could be as high as 15 mg l1. The repeated use of tailing waters without any treatment further increases the dissolved lithium levels in these waters. Some of the lithium minerals are more soluble than the others. Manufacturing of lithium chemicals could contribute to the lithium burden in the environment. Most of the lithium chemicals are often more soluble than lithium minerals, and therefore, the risk to the environment could be higher than the risk introduced by the lithium minerals (see Table 5).
Lithium: Environmental Pollution and Health Effects
Consumer-Created Pollution Man-made lithium pollution sources are mainly from the use of lithium-based grease in vehicles and irresponsible disposal of lithium batteries. Lithium grease is a lubricant to which lithium hydroxide monohydrate is added to give the lubricant higher performance and temperature (190– 220 1C) tolerance. Lithium grease is noncorrosive and generally used under heavy loads and moist conditions. A potential source of lithium posing a threat to the environment is spent lithium batteries. Consumers may indiscriminately dispose of batteries along with other garbage in the municipal solid waste. Spent lithium metal batteries disposed in this manner are generally considered not to pose an environmental or safety hazard. This is based on the assumption that lithium metal (which reacts violently with water to produce explosive hydrogen gas) is no longer reactive as the metallic lithium is converted into a nonreactive lithium oxide once the battery is discharged. However, lithium batteries can often be associated with a variety of heavy metals such as cobalt and manganese, and could contain an organic solvent (propylene carbonate and 1,2-dimethoxyethane), solution of lithium perchlorate, or acetonitrile solution with lithium bromide. The associated compounds of the lithium batteries could be highly toxic. Liquid thionyl chloride vaporizes on exposure to air, and the fumes are highly toxic. Lithium sulfur dioxide batteries typically contain strips of lithium metal as the anode as well as a nonaqueous electrolyte consisting primarily of sulfur dioxide (SO2), smaller concentrations of acetonitrile (CH3CN), and lithium bromide (LiBr). Acetonitrile will decompose to form toxic cyanide fumes when heated. The US Environmental Protection Agency considers spent and discarded lithium sulfur dioxide–type batteries as hazardous waste. Some jurisdictions limit the sale of lithium metal batteries. Carriage and shipment of some types of lithium batteries may be prohibited on aircraft because of the ability of such batteries to fully discharge very rapidly when short-circuited, leading to overheating and possible explosion. Nowadays, the modern lithium batteries have thermal overload protection built in to prevent this type of incident, or their design inherently limits short-circuit currents.
Conclusion Lithium generally has a low toxicity to humans and the environment. However, the combination of the increased use of lithium in psychiatric treatments and its extremely narrow therapeutic window enhances the potential for increased toxicity. In addition, environmental impact is likely to increase as a result of consumer demand for products such as portable electronic devices and hybrid
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vehicles. To minimize this impact, new systems will need to be devised for recycling and reprocessing.
Further Reading Aral H and Vecchio-Sadus A (2008) Toxicity of lithium to humans and the environment – A literature review. Ecotoxicology and Environmental Safety 70: 349--356. Birch NJ (1988) Lithium. In: Seiler HG, Sigel H, and Sigel A (eds.) Handbook on the Toxicity of Inorganic Compounds, pp. 382--393. New York: Marcel Dekker. Domingo JL (1994) Metal-induced developmental toxicity in mammals: A review. Journal of Toxicology and Environmental Health 42: 123--141. Ebensperger A, Maxwell P, and Moscoso C (2005) The lithium industry: Its recent evolution and future prospects. Resources Policy 30: 218--231. Evans, RK (2008) ‘‘Know limits’’ Industrial Minerals, July 2008, pp. 48–55. Evans, RK (2008). An Abundance of Lithium Part 2. www.worldlithium.com/AN_ABUNDANCE_OF_LITHIUM_-_Part_2.html (accessed March 2009). San Diego: R. Keith Evans & Associates. Huh Y, Chan LH, Zhang L, and Edmond JM (1998) Lithium and its isotopes in major world rivers: Implications for weathering and the oceanic budget. Geochimica et Cosmochimica Acta 62: 2039--2051. Kamienski CW, McDonald DP, Stark MW, and Papcun JR (2009) Lithium and lithium compounds. NJ: Kirk-Othmer Encyclopedia of Chemical Technology. Wiley. mrw.interscience.wiley.com/emrw/ 9780471238966/kirk/article/lithkami.a01/current/pdf (accessed March 2009). Kjølholt J, Stuer-Lauridsen F, Skibsted Mogensen A, and Havelund S (2003) The Elements in the Second Rank – Lithium. Miljoministeriet: Copenhagen, Denmark. http://www2.mst.dk/common/ Udgivramme/Frame.asp?http://www2.mst.dk/udgiv/Publications/ 2003/87-7972-491-4/html/bill08_eng.htm (accessed March 2009). Kszos LA and Stewart AJ (2003) Review of lithium in the aquatic environment: Distribution in the United States, toxicity and case example of groundwater contamination. Ecotoxicology 12(5): 439--447. Lagerkvist BJ and Lindell B (2002) The Nordic Expert Group for Criteria Documentation of Health Risks from Chemicals: 131. Lithium and Lithium Compounds. Arbete och Ha¨lsa, vol. 16, 48pp. Arbetslivsinstitutet: Nordic Council of Ministers. Le´onard A, Hantson Ph, and Gerber GB (1995) Mutagenicity, carcinogenicity and teratogenicity of lithium compounds. Mutation Research/Reviews in Genetic Toxicology 339(3): 131--137. Moore JA and IEHR Expert Scientific Committee (1995) An assessment of lithium using the IEHR evaluative process for assessing human developmental and reproductive toxicity of agents. Reproductive Toxicology 9(2): 175--210. National Fire Protection Association (1999). NFPA 485 Standard for the Storage, Handling, Processing and Use of Lithium Metal. MA: National Fire Protection Association. Ribas B (1991) Lithium. In: Merian E (ed.) Metals and Their Compounds in the Environment, 4th ed., pp. 1014--1023. Weinheim: VCH. Schrauzer GN (2002) Lithium: Occurrence, dietary intakes, nutritional essentiality. Journal of the American College of Nutrition 21(1): 14--21. Weiner ML (1991) Overview of lithium toxicology. In: Schrauzer GN and Klippel KF (eds.) Lithium in Biology and Medicine: New Applications and Developments. pp. 83--99. Weinheim: VCH Verlag.
Relevant Websites www.atsdr.cdc.gov/ Agency for Toxic Substances and Disease Registry (ASTDR). www.cdc.gov/ Centers for Disease Control and Prevention (CDC).
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cfpub.epa.gov/ecotox/ ECOTOX. www.lenntech.com/elements-and-water/lithium-and-water.htm Lenntech, Lithium and Water: Reaction Mechanisms, Environmental Impact and Health Effects. www.nlm.nih.gov/databases/databases_medline.html MEDLINE.
www.meridian-int-res.com/Projects/Lithium_Problem_2.pdf Meridian International Research, The Trouble with Lithium. toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?TOXLINE TOXLINE. minerals.usgs.gov/minerals/pubs/commodity/lithium United States Geological Survey, Lithium Statistics and Information.
Abbreviations FDA NIOSH
Food and Drug Administration National Institute for Occupational Safety and Health
It is used in nuclear fusion reactors where tritium is • produced from lithium for the deuterium–tritium fuel
• •
Glossary EC50 Concentration of a material in water, a single dose that is expected to cause a biological effect on 50% of a group of test animals LC50 Lethal concentration, the amount of a substance in air that, when given by inhalation over a specified period of time, is expected to cause the death in 50% of a defined animal population
• • •
Introduction Lithium is present in the earth’s crust at 0.002– 0.006 wt%. It is the 33rd most abundant element in nature and is distributed widely in trace amounts in rocks, soils, and surface, ground, and sea waters. Lithium is enriched in the continental crust over the mantle, especially in pegmatites and in some alkali granitoids where the content reaches a few percentage by weight. Weathering of rocks containing lithium-rich minerals releases lithium to the environment. As a result, lithium is found in varying amounts in all soils, primarily in the finer particle size fractions. Carbonates and calcareous shales precipitated from evaporated seawater or lagoon water can have higher lithium concentrations. Lithium has widespread use, which in turn affects the environment and the health of fauna and flora:
• • • • •
It is used as a flux to promote the fusing of metals during welding and soldering, as it prevents the formation of oxides during welding by absorbing impurities. It is used in glass and ceramics, including the glass for the 5.08 m telescope at Palomar Observatory in San Diego, California. It can be used to give red color to fireworks. Lithium metal is used as a reducing agent in illegal, amateur ‘methamphetamine labs.’ It is used as a catalyst in the production of synthetic rubber and plastics.
• • •
•
cycle. Lithium compounds are used in the medical treatment of bipolar disorder. Lithium stearate is a high-temperature lubricant grease used in military, industrial, automotive, aircraft, and marine applications. The lithium-based grease does not become hard when cooled, and it does not react with water or oxygen in the air. Lithium stearate is used as an additive in cosmetics and plastics. Lithium batteries are disposable (primary) batteries that have lithium metal or lithium compounds as an anode. Lithium-ion batteries are high-energy-density rechargeable batteries. Lithium–lead alloys are used to make tough ball bearings for machinery. Lithium–aluminum and lithium–magnesium alloys are very light but strong, and are used largely in making armored vehicles and in aerospace applications. Alloys of lithium with aluminum, cadmium, copper, and manganese are used in various aircraft parts. Lithium chloride and lithium bromide absorb moisture from air and are used as desiccants. Lithium niobate is used extensively in mobile phones and optical modulators as resonant crystals. Lithium niobate is also used to make optical glass. Lithium peroxide, lithium nitrate, lithium chlorate, and lithium perchlorate are used as oxidizing agents in rocket propellants and in providing oxygen to submarines and space capsules. Metallic lithium and LiAlH4 are also used as rocket propellants. Lithium peroxide (Li2O2) in the presence of moisture absorbs carbon dioxide to form lithium carbonate and release oxygen. Lithium hydroxide (LiOH) when heated with a fat produces lithium soap, which is used to thicken oils and is used commercially to manufacture lubricating greases. Lithium hydroxide absorbs carbon dioxide from the air by reacting with it to form lithium carbonate.
Details on various applications of major lithium products are shown in Table 1. Over the past decade, the production and the consumption of lithium have increased at an average of approximately 3% per annum. The increase in the production of lithium and its compounds is driven
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Table 1
Various applications of lithium and their indicative values
Application
Main compound
Glass/ceramics melting points Glass/ceramics glazing Aluminum Lubricants Batteries Pharmaceuticals Air-conditioning Synthetic rubber Other
Lithium Lithium carbonate Lithium carbonate Lithium hydroxide Lithium carbonate Butyllithium Lithium bromide Butyllithium Lithium carbonate
Volume (%)
Amount (thousand tons)
Estimated price (US$ kg1)
Estimated value (million US$)
8
5.8
2
11
13 6 17 12 5 11 5 18
9.4 4.3 12.2 8.6 3.6 7.9 3.6 13
2 2 4 12 15 6 15 3
18 8 48 101 53 46 53 38
Source: From Ebensperger A, Maxwell P, and Moscoso C (2005) The lithium industry: Its recent evolution and future prospects. Resources Policy 30: 218–231, with permission from Pergamon.
primarily by the battery industry. For example, there are millions of mobile phones, laptop computers, and cameras in use around the world that use lithium batteries (Figure 1). There is also an emerging use of lithium as a power storage device in electric and hybrid vehicles.
Sources of Lithium Lithium is found naturally in the aquatic and terrestrial environments, but in small concentrations (Table 2). Lithium is found primarily in ionic form in water. The lithium concentration in freshwater and seawater is on the microgram per liter level. Surface water contains lithium at levels between 1 and 10 mg l1, seawater contains approximately 0.18 mg l1 lithium, and the lithium concentrations in groundwater may reach 0.5 mg l1. Lithium in the aquatic environment in the United States has been detected at low concentrations (B0.002 mg l1) in the major rivers and at typically o0.04 mg l1 in surface waters, but could be higher in contaminated streams. Worldwide, mineral water contains 0.05–1.0 mg l1 lithium; however, higher levels up to 100 mg l1 can be found in some natural mineral waters. Some bottled mineral waters may contain 0.002–5.2 mg l1 dissolved lithium. The intake from drinking tap water has been reported to be from less than 0.001 to approximately 0.3 mg Li per day. However, very high intake via drinking water, more than 5 mg Li per day, has been reported in areas of northern Chile with lithium-rich soils. Intake from municipal drinking water in northern Chile could be up to 1.4 mg Li per day. Lithium could be leached to these waters from weathered lithium minerals in alkali granitic rocks and lithium-rich clays and soils. Rivers generally contain approximately 3 mg l1 Li, whereas in the lithium-rich soils of northern Chile, the lithium content of the surface waters could be as high as 6 mg l1. High concentrations of lithium may also occur
in waters sourcing from rocks that are inherently rich in lithium. The lithium concentration in major rivers varied from 0.67 mg l1 for the Amazon River to 0.87 mg l1 for the Congo, 4.0 mg l1 for the Ganges, and 5.6 mg l1 for the Mississippi River. The concentration of lithium in lakes could be higher due to evaporation. The concentration of lithium in major lakes is shown in Table 3. Lithium is found in natural brines (Salar de Atacama, Chile; Salar de Hombre Muerto; and Salar de Rincon, Argentina, in South America and Searle’s Lake and Clayton Valley in the USA) and lakes (Great Salt Lake, USA; Zabuye Lake, Tibet; Dachaidan, China; Dead Sea, Israel). The lithium content of these brines varies from 20 mg l1 in the Dead Sea to 1500 mg l1 in Salar de Atacama. Processing of brines and lithium-rich lakes may enhance the dispersion of lithium to a wider area and could cause environmental pollution. Thermal springs and volcanic fumaroles can contain higher levels of lithium than background levels. For example, in the sulfate-rich waters of the Mendelev volcano in Kuril Island (Russia), the lithium content reaches 927 mg l1. In the same springs, rubidium and barium concentrations are also high. In the Stolbovskie springs, Li content ranges between 264 and 398 mg l1. Lithium is enriched in the continental crust over the mantle, especially in pegmatites, the highly coarsegrained and relatively light-colored crystalline rocks composed mainly of minerals found in ordinary igneous rocks. In some alkali granitoids, the lithium content may reach up to several percentage by weight. Lithium tends to enter the mineral structure of pyroxenes and amphiboles, replacing Mg2þ and Fe2þ and later Al3þ sites, muscovites, and plagioclases. In the case of excess lithium in the magmatic melt, lithium forms its own minerals such as spodumene (LiAlSi2O6), petalite (LiAlSi4O10), amblygonite ((Li,Na)Al(F,OH)PO4), montebrasite (LiAl (PO4)(OH,F)), lithiophilite (LiMnPO4), and lepidolite (K(Li,Al)3(Si,Al)4O10(F,OH)2). Weathering of rocks containing these minerals releases lithium to the
Lithium: Environmental Pollution and Health Effects
Figure 1
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Various sizes and shapes of lithium batteries used in electronic equipment.
Table 2 Typical background concentrations of lithium in the environment Environment
Concentration
Freshwater (mg l1) Seawater (mg l1) Sediment (mg kg1) Soil (mg kg1) Earth’s crust (mg kg1) Atmosphere (ng m3)
0.07–40 0.17–0.19 56 3–350 20–60 2
Source: From Aral H and Vecchio-Sadus A (2008) Toxicity of lithium to humans and the environment - A literature review. Ecotoxicology and Environmental Safety 70: 349–356, with permission from Elsevier.
environment. Carbonates precipitated from evaporated lake water can have high lithium concentrations, as demonstrated by a Dead Sea aragonite with 19 ppm lithium. Calcareous shales from the Ellis Group of Yellowstone National Park have been shown to contain approximately 18 ppm lithium. Lithium is found in trace amounts in all soils, primarily in the clay fraction, and to a lesser extent in the organic soil fraction, in amounts ranging from 7 to
Table 3
Lithium concentrations of the world’s major lakes
Name
Li (mg l1)
Lake Tanganyika Caspian Sea Lake Baikal Dead Sea
0.014 0.280 2.0 14.0
200 mg g1. Sediments in sabkhas and evaporite deposits of lagoons may contain elevated levels of lithium along with boron, potassium, and magnesium salts. Authigenic clays (i.e., those occurring in the place where they were originally formed) are enriched in lithium (200–500 ppm in smectites) relative to other rock types (e.g., igneous rocks 30 ppm and detrital clays 70–80 ppm). Liþ has the weakest sorption chemistry of all the alkali metals, and its affinity with clays is considered to be due to the isomorphic substitution of Mg2þ for Al3þ in the octahedral layer, leaving a vacant position to accommodate Liþ. Lithium is selectively absorbed over other cations and apparently fixed in a non exchangeable form. Adsorption onto suspended sediments in rivers may also play a role, but preliminary experiments have suggested that only
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approximately 1 ppm lithium is adsorbed onto clays and riverbed sediments. Lithium concentrations are generally in proportion to magnesium concentrations due to ionic radius similarities, but are only poorly correlated with other major ions, for example, with silicon and potassium, even though lithium concentrations result almost exclusively from the weathering of aluminosilicates. This is consistent with the tendency of lithium to be retained in secondary clays, substituting for Mg2þ or occupying the vacancy generated by Mg2þ substitution of Al3þ. Lithium ore minerals are mined around the world in various places to make various lithium products. Mines are located in places such as Manona, Zaire; Bikita, Zimbabwe; Greenbushes, Western Australia; La Corne and Bernic Lakes, Canada; Kola Peninsula, Russia; and Altai Mountains, China. It has been reported that the total lithium reserve of the world is 29.8 million tons (Table 4), which is equal to approximately 1500 years’ supply at the current consumption rate of approximately 20 000 tons per annum. Spodumene and brine are processed to form a number of products for domestic and industrial use (see Figure 2).
Table 4
Lithium reserves of the world
Deposit
Li (million tons)
Pegmatites Continental brines Geothermal brines Oil field brines Hectorites Jadarite
7.60 17.59 1.00 0.75 2.00 0.85
Li2CO3 Glass Ceramics Aluminum C.C. Powder Batteries Glass Airconditioning Ceramics Chemicals Adhesives
Natural resources
Minerals (spodumene, etc.)
Brines
Lithium carbonate Li2CO3
Basics
Lithium Chemicals There are numerous lithium-based chemicals used in a variety of applications. Most of these chemicals dissolve in water in considerable amounts (Table 5). Lithium metal reacts slowly with water to form lithium hydroxide and hydrogen. Metallic lithium reacts with nitrogen gas at room temperature to form a black nitride. Lithium nitride in turn reacts with water to form ammonia and lithium hydroxide. Lithium metal can ignite spontaneously in damp air. Lithium reacts with ammonia to form the amide, which on heating yields ammonia and lithium imide (Li2NH). At 500–700 1C, lithium reacts with hydrogen to form lithium hydride. Lithium hydride is an odorless, off-white to gray crystalline solid or a white powder. Airborne dust clouds of lithium hydride may explode on contact with heat. In the presence of moisture, lithium hexafluoroarsenate has the potential to form hydrogen fluoride, a highly corrosive gas. Lithium metal is flammable and potentially explosive when suddenly exposed to air and especially to water. The lithium–water reaction at normal temperatures is vigorous. Lithium fires are difficult to extinguish and require special chemicals designed to smother them. Metallic lithium is classified as a health, physiochemical, or ecotoxicological hazard. Lithium compounds such as lithium aluminum hydride and lithium methanolate are classified as dangerous goods. Lithium salts are not very toxic, except for the highly corrosive and irritant lithium hydrides, lithium tetrahydroaluminate (LiAlH4), and lithium tetrahydroborate (LiBH4). Spodumene, the major lithium ore mined in various places around the world, is an aluminum silicate.
Performance Secondary batteries Pharmaceutical Several
Specialty inorganics Greases
Bar/sheet
Lithium hydroxide LiOH Lithium chloride LiCl
Metal lithium
Primary batteries Aleacionesdealuminio Secondary batteries
Butyl lithium
Polymers Pharmaceutical
Specialty inorganics
Polymers Pharmaceutical
Pharmaceutical Gases separation Dehumidification Fluxesundentes
Figure 2 Processing of spodumene and brine sources to value-added products. C.C. Powder, ceramic coating powder. From Ebensperger A, Maxwell P, and Moscoso C (2005) The lithium industry: Its recent evolution and future prospects. Resources Policy 30: 218–231, with permission from Pergamon. .
Lithium: Environmental Pollution and Health Effects Table 5
Water solubility of some lithium compounds
Substance
Solubility in water
Lithium Lithium hydride Lithium acetate Lithium oxide Lithium hydroxide Lithium hydroxide monohydrate Lithium carbonate Lithium bromide Lithium chloride Lithium fluoride Lithium nitrate Lithium stearate
Decomposes to LiOH and H2 Decomposes to LiOH and H2 3000 g l1 (15 1C) 66.7 g l1 (0 1C); 100.2 g l1 (100 1C) 128 g l1 (20 1C); 175 g l1 (100 1C) 223 g l1 (10 1C); 268 g l1 (80 1C) 15.4 g l1 (0 1C); 7.2 g l1 (100 1C) 1450 g l1 (4 1C); 2540 g l1 (90 1C) 637 g l1 (0 1C); 1300 g l1 (96 1C) 2.7 g l1 (18 1C) 898 g l1 (28 1C); 2340 g l1 (100 1C) 0.1 g l1 (18 1C)
Source: Weast RC (1987) Handbook of Chemistry and Physics, 68th edn. Boca Raton, FL: CRC Press. 1987.
Table 6 Solubility (24 h, 40 1C) of various lithium minerals in water and various concentrations of sulfuric acid Sample lithium mineral concentrate
Aqueous reagent
Dissolved Li (mg l 1)
Spodumene
Distilled H2O 0.01 M H2SO4 0.1 M H2SO4 1.0 M H2SO4 Distilled H2O 2.5 M H2SO4 Distilled H2O 2.5 M H2SO4 0.01 M H2SO4 2.5 M H2SO4 0.01 M H2SO4
1.5 5.8 8.8 12.0 41.0 975 13.6 358 80.0 633 1.9
Amblygonite Lepidolite Lithiophilite Petalite
It contains up to 8.0 wt% Li2O, and this lithium is tightly bound to the crystal structure, and therefore, it alone does not pose a toxicological problem. However, when spodumene is crushed, it generates silica-rich dust, which is a health hazard. Finely ground lithium minerals, especially lithium-containing phosphate ores, are more susceptible to water and dilute acid leaching than unground ores due to increased surface area (Table 6).
Sources and Routes of Lithium Exposure People can be exposed to lithium through occupational, environmental, consumer, and medical sources. Occupational exposure to lithium occurs during the extraction of crude oil and natural gas, mining and processing of lithium minerals, and battery production. Environmental sources of exposure to lithium are primarily from soil and water. Consumer exposure could potentially occur from the use of products containing lithium (e.g., batteries and grease) and from mineral supplements.
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Medical exposure to lithium occurs through therapeutic applications. Occupational exposures to lithium may occur during extraction of lithium from ores, preparation of lithium compounds, welding, and enameling. In industrial environments such as mines and processing plants, workers and maintenance personnel may come in direct contact with lithium-containing dust. A NIOSH (National Institute for Occupational Safety and Health) study identified that workers in a lithium-processing plant experienced an estimated daily dose of 0.000 16–0.82 mg Li per kg of bodyweight. During welding, lithium vapors may be emitted from lithium-containing fluxes. The red color of firecrackers is mostly produced from the use of metallic lithium. Considerable amounts of lithium are discharged to the environment during New Year celebrations. The inhalation of lithium compounds and the ingestion of inhaled particles are most likely to take place through occupational exposures. The food humans consume, the water they drink, and the air they breathe may contain more than average levels of lithium, depending on the location. Occupational and natural lithium emissions may result in lithium concentrations in water and soils. Exposure routes to humans may include inhalation of dust, ingestion of contaminated water, or ingestion of foods grown in contaminated soils. There is negligible inhalation of lithium from air as ambient air levels are low (2–4 ng m3). In places where lithium brines crystallize by evaporation, the lithium content of the air could be higher. There is negligible absorption of lithium through the skin. Lithium may be found in some plants and animals in higher concentrations than the average, depending on the geographical location. A number of studies from different countries have reported intake levels from food ranging from 0.02 to 0.54 mg Li per day. An American assessment found that the average daily lithium intake of a 70 kg adult (American) is between 0.65 and 3.1 mg per day. Major dietary sources of lithium are grains and vegetables (0.5–3.4 mg Li per kg food), dairy products (0.50 mg Li per kg food), and meat (0.012 mg Li per kg food). In places like Chile where lithium-rich salinas could contain up to 1500 mg l1 Li, the total lithium intake may reach 10 mg kg1 without evidence of adverse effects to the local population. A review of the dietary intake of lithium has indicated that the minimum human adult (physiological) lithium requirement is estimated to be less than 0.1 mg per day. Based on lithium intake data in different countries, a provisional recommended daily intake of 1.0 mg Li per day for a 70 kg adult American was proposed, corresponding to 14.3 mg kg1 bodyweight, which can be derived by diet alone. People on special diets or populations residing in naturally low-lithium areas would require lithium supplements or other appropriate measures to meet this intake. Lithium levels in
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humans may be higher after physical exertion, in certain diseases and in dialysis patients. The highest exposure to lithium generally results from oral intake in therapeutic doses, although total lithium exposure and body burden is also geographically variable. Reported Li levels in serum of healthy subjects generally range from 1.1 to 59.7 mg l1, but levels up to 83 mg l1 have been reported, with the highest levels found in Chile. The typical plasma Li concentration is 14–21 mg l1. After oral administration of immediate-release lithium tablets, the maximal plasma concentrations are 1000-fold greater than typical trace concentrations. Consumption of mineral supplements could result in an additional internal dose of 5–6 mg Li per day.
Toxicity and Health Effects of Lithium Exposure Lithium does not have a known biological use and does not appear to be an essential element for human life. The amount of lithium in the human body is approximately 7 mg. Lithium is absorbed from the gastrointestinal tract and excreted primarily through the kidneys after approximately 24 h. Serum concentrations of lithium reach a peak approximately 30 min after oral ingestion, followed by a plateau at 12–24 h. Lithium ions cross the cell membrane slowly; this may account not only for the prolonged excretion of lithium but also for the delay of 6–10 days needed to achieve the full therapeutic response in humans. Although lithium is not an essential element, it may influence metabolism. A great deal of knowledge surrounding the toxicity of lithium has emerged from its extensive use in the medical industry. Lithium was first introduced into the medical profession in the mid-1800s as a cure-all for many common illnesses. The therapeutic levels of lithium are clearly able to inhibit functioning of multiple enzymes in the body. Lithium, as a medicine, has multiple effects on embryonic development, glycogen synthesis, hematopoiesis (the formation and development of blood cells involving both proliferation and differentiation from stem cells), and other processes. Common side effects of lithium treatment include muscle tremors, twitching, ataxia, bone loss, kidney damage, nephrogenic diabetes insipidus (polyuria and polydipsia), and seizures. Many of the side effects are the result of increased elimination of potassium. In 1949, lithium was banned from use in the United States because of excessive toxicity and did not gain FDA (Food and Drug Administration) approval for use in the treatment of mania until 1970. For more than 50 years, lithium has been the drug of choice for the treatment of recurrent bipolar disorder and has gained popularity as a pharmacologic option in the treatment of other psychiatric conditions because the
primary target organ for lithium is the central nervous system. Lithium salts, especially lithium carbonate and lithium acetate, are used extensively in the treatment of manic-depressive disorders. In the medical use of lithium salts, lithium ion Liþ, which has a smaller diameter, displaces Kþ and Naþ and in some cases Ca2þ, Mg2þ, and Zn2þ, in various enzymes. The therapeutic window between effective lithium dose and lithium toxicity is narrow. The therapeutic serum concentrations are normally approximately 5.6–8.4 mg l1, mild toxicity is usually seen at approximately 10.5–17.5 mg l1, moderate toxicity is seen at approximately 17.5–24.5 mg lF1, and severe symptoms are seen at 424.5 mg l1. Side effects are common even within the therapeutic dose range, and a significant number of patients do not respond. In one example, the vast majority (75–90%) of patients receiving maintenance lithium therapy for bipolar disorder became toxic at some point during their course of therapy. In 1996, 5102 lithium exposures were reported to the American Association of Poison Control Centers, with nearly 75% of those suffering exposure seeking medical attention.
Epidemiology Epidemiological studies have not clearly established a relationship between naturally occurring lithium and its positive or negative effects on humans. Limited information on possible carcinogenic and genetic effects of lithium compounds has been published to date. Most of the existing epidemiological studies were performed on laboratory animals. Study of incidents relating to human gender, race, and social status is rare.
Teratogenicity Teratogenicity is the ability to cause defects in a developing fetus. It is a potential side effect of many drugs such as thalidomide. Many authors have reported that lithium causes congenital defects, especially of the cardiovascular system such as Ebstein’s anomaly (a rare cardiac defect), when given to women during the first trimester of pregnancy. This claim gave rise to the foundation of a ‘Register of Lithium Babies’ in Risskov (Denmark) and later of an ‘American Registry of Lithium Babies’ in San Francisco. A first analysis (published in 1971) of the records of 60 children born by mothers who received lithium treatment during the first trimester or the entire pregnancy did not reveal any association of lithium treatment with a higher teratogenic risk. A multicenter study of pregnancy outcome after therapeutic lithium exposure during the first trimester also did not show any significant teratogenic risk.
Lithium: Environmental Pollution and Health Effects
Mutagenicity Mutagenicity is the ability to cause genetic mutations in sperms, eggs, and other cells. Despite the extensive therapeutic use of lithium carbonate, few investigations on the mutagenic potential of lithium compounds have been carried out. Lithium could have several ways of acting on DNA: Liþ binds selectively to DNA; it competes with Mg2þ and may impair DNA synthesis and DNA repair. Lithium carbonate added at the start of a 72 h culture period at concentrations equivalent to 0.1, 1.0, or 10 g of lithium carbonate distributed in the body of a 70 kg person did not increase structural chromosome aberrations in peripheral lymphocytes. No aberrations were found in 19 lithium-treated manic-depressive patients compared with 23 controls, but the mitotic index was significantly reduced. Similarly, no aberrations were observed in peripheral lymphocytes of as many as 77 patients studied, 50 of whom had been treated with lithium sulfate, 17 with lithium carbonate, and 10 with lithium acetate. Also, 16 manic-depressive patients who had been given lithium carbonate from 2 weeks to more than 2 years (seven of them for more than a year) did not show aberrations in their lymphocytes.
Environmental Pollution and Toxicology Geochemically, lithium is a highly mobile element; hence, lithium in aquatic environments can be transported long distances from the source. There are potential environmental impacts from the increased mining and use of lithium and its compounds. Increased levels of lithium in aquatic and terrestrial environments would affect the food chain. High lithium levels in soil may be phytotoxic and reduce biomass in crops.
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(Ptychocheilus lucius), razorback sucker (Xyrauchen texanus), and bonytail (Gila elegans) in the water simulating the middle Green River. This study showed that the overall rank order of toxicity to all species and life stages combined from most to least toxic was vanadium ¼ zinc 4 selenite 4 lithium ¼ uranium 4 selenate 4 boron. Studies have identified lithium toxicity levels in certain organisms (Table 7). Effective concentration (EC50) is the concentration of a material in water, a single dose that is expected to cause a biological effect on 50% of a group of test animals. Lethal concentration (LC50) is the amount of a substance in air that, when given by inhalation over a specified period of time, is expected to cause the death in 50% of a defined animal population. The presence of sodium is sufficient to prevent lithium toxicity to Pimephales promelas (fathead minnow), Ceriodaphnia dubia, and Elimia clavaeformis (a freshwater snail) in most natural waters. The acute environmental effect concentration (measured as EC50) on Daphnia magna was determined to be 33–197 mg l1, which is at least 1000 times higher than the level in freshwater. Both lithium chloride and lithium sulfate have high water solubility, and the compounds will dissociate in aqueous environment. No lithium compounds are classified for adverse environmental effects. No data regarding bioaccumulation of lithium were found, but based on its low affinity to particles, it is not expected to bioaccumulate. In Salar de Uyuni in Bolivia, lithium is dispersed over a 9000 km2 salt flat at 3600 m altitude in the Andes. Salar de Uyuni is classified by the tourist industry as a land of outstanding natural beauty. The area becomes a flamingo breeding ground from December to February when the rain floods the surface of the salar between January and March. The discharge of the Rio Grande into the salar, adjacent to where the lithium concentration is highest, creates a permanent lagoon area used by the birds.
Aquatic Environment Investigations were carried out on the acute toxicity of boron, lithium, selenate, selenite, uranium, vanadium, and zinc to early stages of development of Colorado squaw fish
Table 7
Terrestrial Environment Lithium is taken up by all plants, although it is not an essential nutrient for their growth and development. In
Test results for environmental (aquatic) toxicity
Species
Latin name (common name)
Compound
Exposure duration
EC50 (mg l1)
Mollusc
Dreissena polymorpha (zebra mussel) Daphnia magna (water flea) Tubifex tubifex (tubicid worm) Pimephales promelas (fathead minnow) Tanichthys albonubes (white cloud mountain minnow)
LiCl
24 h
–
Li2SO4 Li2SO4 LiCl
24 h 24–96 h 26 days
LiCl
48 h
Crustacean Worm Fish
33–197 9.3–44.8 1–6.4 –
LC50 (mg l1) 185–232 – – 1.2–8.7 9.2–62
Source: From Aral H and Vecchio-Sadus A (2008) Toxicity of lithium to humans and the environment – A literature review. Ecotoxicology and Environmental Safety 70: 349–356, with permission from Elsevier.
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some cases, stimulation of plant growth has been observed. Lithium is relatively toxic to citrus plants. The amount of lithium in plants usually lies between 0.2 and 30 ppm due to preferential uptake or rejection across species. Plants such as Cirsium arvense and Solanum dulcamera accumulate lithium in concentrations of three- to sixfold over other plants. Nightshade species may reach concentrations of up to 1 mg g1. Salt-tolerant plants such as Carduus arvense and Holoschoenus vulgaris may reach lithium contents of 99.6–226.4 mg g1. Lithium concentrations vary widely from 0.01 ppm (dry basis) in bananas to 55 ppm in oats. There appears to be a greater uptake of lithium by plants in acidic soils. Soil acidity increases the solubility of the heavier metallic elements such as iron, nickel, cobalt, manganese, and copper, and to some extent also aluminum, lead, and cadmium. Plant lithium levels are directly and significantly correlated with the concentrations of these elements. Calcium can be added to soils to prevent toxicity and the uptake of lighter minerals. Lithium in plants and animals interacts with sodium and potassium as well as with enzymes requiring magnesium. Its complexing properties are stronger than those of Naþ and Kþ but weaker than those of Mg2þ. At concentrations attained during therapy, Liþ and Mg2þ are present in comparable concentrations; thus, Liþ binds to sites not occupied by Mg2þ. Once all Mg2þ sites are saturated, Liþ substitutes for Naþ and Kþ. All alkali metal ions are exchanged more than 1000 times more rapidly than Mg2þ; this may explain why lithium preferentially affects the activity of Mg2þ-containing enzymes. Chlorophyll mutants were produced in the progeny of Pisum abyssinicum plants treated with lithium nitrate in addition to other nitrates (Cu, Zn, Cr, Mn, Fe, Co, Ni, and Al). This was most likely due to the presence of the other confirmed mutagenic metal nitrates. Yeast (Saccharomyces cerevisiae) has been shown to take up limited amounts of lithium, with growth inhibition exhibited at high levels (115–400 ppm). A high ability to accumulate lithium was exhibited by strains of the bacteria Arthrobacter nicotianae (B1.0 mg g1 dry weight cells) and Brevibacterium helvovolum (B0.7 mg g1 dry weight cells). Exposure of earthworms (Eisenia fetida) to lithium chloride identified a mortality rate at concentrations of approximately B70 mg kg1 soil. A limited investigation of the levels of lithium and other elements in major emissions and waste streams was conducted in Denmark in 2001. In the Danish study, lithium was found in all environmental samples especially compost, wastewater, sewage sludge, and sediment from road runoff retention basins (Table 8). The concentration in effluent from wastewater treatment plants was low and was not considered as being acutely toxic to aquatic organisms.
Table 8 Levels of lithium in selected emissions and waste products in Denmark Emission/waste type
Li concentration
Compost: Compost from household waste 4.64 mg kg1 Compost from garden waste 4.69 mg kg1 Landfill leachate: Landfill 1 0.2 mg l1 Landfill 2 0.049 mg l1 Stack gas from municipal solid waste incineration: Incinerator 1, semidry gas cleaning o9.1 mg m3 Incinerator 2, wet gas cleaning 1.0 mg m3 Municipal solid waste gas cleaning residuals: Landfill leachate, semidry gas cleaning 0.285 mg l1 Landfill leachate, wet gas cleaning 0.367 mg l1 Wastewater and sludge from municipal wastewater treatment plant: Plant 1, effluent 11.4 mg l1 Plant 2, effluent 21.2 mg l1 Plant 1, sludge 6.06 mg kg1 Plant 2, sludge 5.02 mg kg1 Road runoff retention basins, sediment: Motorway 1 16.3 mg kg1 Motorway 2 15.5 mg kg1 Source: From Aral H and Vecchio-Sadus A (2008) Toxicity of lithium to humans and the environment – A literature review. Ecotoxicology and Environmental Safety 70: 349–356, with permission from Elsevier.
Mining-Related Pollution Mining and mineral-processing industries producing lithium minerals, metals, and salts contribute to the lithium burden in the environment. The processing of lithium-containing minerals such as spodumene, in general, comprises crushing, wet grinding in a ball mill, sizing, gravity concentration, and flotation using a fatty acid (oleic acid) as the collector. The major lithium mineral in lithium ore is spodumene, which is considered insoluble in water and dilute acids. However, a small amount of dissolution may occur during processing of the ore especially in the grinding and flotation stages where some dilute (0.01 M) sulfuric acid is used (see Table 6). Tailings are discharged to storage areas, and the decanted water is usually recovered for reuse. Lithium concentrations in tailing dams increase gradually. The dissolved lithium found in the tailing dams of lithium mineral beneficiation plants could be as high as 15 mg l1. The repeated use of tailing waters without any treatment further increases the dissolved lithium levels in these waters. Some of the lithium minerals are more soluble than the others. Manufacturing of lithium chemicals could contribute to the lithium burden in the environment. Most of the lithium chemicals are often more soluble than lithium minerals, and therefore, the risk to the environment could be higher than the risk introduced by the lithium minerals (see Table 5).
Lithium: Environmental Pollution and Health Effects
Consumer-Created Pollution Man-made lithium pollution sources are mainly from the use of lithium-based grease in vehicles and irresponsible disposal of lithium batteries. Lithium grease is a lubricant to which lithium hydroxide monohydrate is added to give the lubricant higher performance and temperature (190– 220 1C) tolerance. Lithium grease is noncorrosive and generally used under heavy loads and moist conditions. A potential source of lithium posing a threat to the environment is spent lithium batteries. Consumers may indiscriminately dispose of batteries along with other garbage in the municipal solid waste. Spent lithium metal batteries disposed in this manner are generally considered not to pose an environmental or safety hazard. This is based on the assumption that lithium metal (which reacts violently with water to produce explosive hydrogen gas) is no longer reactive as the metallic lithium is converted into a nonreactive lithium oxide once the battery is discharged. However, lithium batteries can often be associated with a variety of heavy metals such as cobalt and manganese, and could contain an organic solvent (propylene carbonate and 1,2-dimethoxyethane), solution of lithium perchlorate, or acetonitrile solution with lithium bromide. The associated compounds of the lithium batteries could be highly toxic. Liquid thionyl chloride vaporizes on exposure to air, and the fumes are highly toxic. Lithium sulfur dioxide batteries typically contain strips of lithium metal as the anode as well as a nonaqueous electrolyte consisting primarily of sulfur dioxide (SO2), smaller concentrations of acetonitrile (CH3CN), and lithium bromide (LiBr). Acetonitrile will decompose to form toxic cyanide fumes when heated. The US Environmental Protection Agency considers spent and discarded lithium sulfur dioxide–type batteries as hazardous waste. Some jurisdictions limit the sale of lithium metal batteries. Carriage and shipment of some types of lithium batteries may be prohibited on aircraft because of the ability of such batteries to fully discharge very rapidly when short-circuited, leading to overheating and possible explosion. Nowadays, the modern lithium batteries have thermal overload protection built in to prevent this type of incident, or their design inherently limits short-circuit currents.
Conclusion Lithium generally has a low toxicity to humans and the environment. However, the combination of the increased use of lithium in psychiatric treatments and its extremely narrow therapeutic window enhances the potential for increased toxicity. In addition, environmental impact is likely to increase as a result of consumer demand for products such as portable electronic devices and hybrid
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vehicles. To minimize this impact, new systems will need to be devised for recycling and reprocessing.
Further Reading Aral H and Vecchio-Sadus A (2008) Toxicity of lithium to humans and the environment – A literature review. Ecotoxicology and Environmental Safety 70: 349--356. Birch NJ (1988) Lithium. In: Seiler HG, Sigel H, and Sigel A (eds.) Handbook on the Toxicity of Inorganic Compounds, pp. 382--393. New York: Marcel Dekker. Domingo JL (1994) Metal-induced developmental toxicity in mammals: A review. Journal of Toxicology and Environmental Health 42: 123--141. Ebensperger A, Maxwell P, and Moscoso C (2005) The lithium industry: Its recent evolution and future prospects. Resources Policy 30: 218--231. Evans, RK (2008) ‘‘Know limits’’ Industrial Minerals, July 2008, pp. 48–55. Evans, RK (2008). An Abundance of Lithium Part 2. www.worldlithium.com/AN_ABUNDANCE_OF_LITHIUM_-_Part_2.html (accessed March 2009). San Diego: R. Keith Evans & Associates. Huh Y, Chan LH, Zhang L, and Edmond JM (1998) Lithium and its isotopes in major world rivers: Implications for weathering and the oceanic budget. Geochimica et Cosmochimica Acta 62: 2039--2051. Kamienski CW, McDonald DP, Stark MW, and Papcun JR (2009) Lithium and lithium compounds. NJ: Kirk-Othmer Encyclopedia of Chemical Technology. Wiley. mrw.interscience.wiley.com/emrw/ 9780471238966/kirk/article/lithkami.a01/current/pdf (accessed March 2009). Kjølholt J, Stuer-Lauridsen F, Skibsted Mogensen A, and Havelund S (2003) The Elements in the Second Rank – Lithium. Miljoministeriet: Copenhagen, Denmark. http://www2.mst.dk/common/ Udgivramme/Frame.asp?http://www2.mst.dk/udgiv/Publications/ 2003/87-7972-491-4/html/bill08_eng.htm (accessed March 2009). Kszos LA and Stewart AJ (2003) Review of lithium in the aquatic environment: Distribution in the United States, toxicity and case example of groundwater contamination. Ecotoxicology 12(5): 439--447. Lagerkvist BJ and Lindell B (2002) The Nordic Expert Group for Criteria Documentation of Health Risks from Chemicals: 131. Lithium and Lithium Compounds. Arbete och Ha¨lsa, vol. 16, 48pp. Arbetslivsinstitutet: Nordic Council of Ministers. Le´onard A, Hantson Ph, and Gerber GB (1995) Mutagenicity, carcinogenicity and teratogenicity of lithium compounds. Mutation Research/Reviews in Genetic Toxicology 339(3): 131--137. Moore JA and IEHR Expert Scientific Committee (1995) An assessment of lithium using the IEHR evaluative process for assessing human developmental and reproductive toxicity of agents. Reproductive Toxicology 9(2): 175--210. National Fire Protection Association (1999). NFPA 485 Standard for the Storage, Handling, Processing and Use of Lithium Metal. MA: National Fire Protection Association. Ribas B (1991) Lithium. In: Merian E (ed.) Metals and Their Compounds in the Environment, 4th ed., pp. 1014--1023. Weinheim: VCH. Schrauzer GN (2002) Lithium: Occurrence, dietary intakes, nutritional essentiality. Journal of the American College of Nutrition 21(1): 14--21. Weiner ML (1991) Overview of lithium toxicology. In: Schrauzer GN and Klippel KF (eds.) Lithium in Biology and Medicine: New Applications and Developments. pp. 83--99. Weinheim: VCH Verlag.
Relevant Websites www.atsdr.cdc.gov/ Agency for Toxic Substances and Disease Registry (ASTDR). www.cdc.gov/ Centers for Disease Control and Prevention (CDC).
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cfpub.epa.gov/ecotox/ ECOTOX. www.lenntech.com/elements-and-water/lithium-and-water.htm Lenntech, Lithium and Water: Reaction Mechanisms, Environmental Impact and Health Effects. www.nlm.nih.gov/databases/databases_medline.html MEDLINE.
www.meridian-int-res.com/Projects/Lithium_Problem_2.pdf Meridian International Research, The Trouble with Lithium. toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?TOXLINE TOXLINE. minerals.usgs.gov/minerals/pubs/commodity/lithium United States Geological Survey, Lithium Statistics and Information.